Trough washer



Max-( :11 19, 1940. 1N. DAVIS ETAL THOUGH WASHER Filed March 7, 1938 2 Sheets-Sheet 1 Matt]! 19, 1940. N- L. D Er m.

TROUGH WASHER Filed March '7, 19

758 2 Sheets-Sheet 2 unnnmm unuuuun *45 unuunng was 49 HIJIJUH Patented Mar. 19, 1940 PATENT OFFICE 2,194,139 TROUGHWASHER Nelson L. Davis, James D. S. Drinkwater, and

Thomas 0. Carlisle, Chicago, Ill., assign'ors to Link-Belt Company,- Chicago,- Ill., a corporation of Illinois Application March 7, 1938, Serial No. 194,358

3 Claims. (Cl. 83-94) Our invention relates to improvements in ore dressing apparatuses and processes. plicable especiallyto the cleaning of coal but may be applied to the treatment of other comminuted materials.

There is an increased interest in the treatment of very large capacities and at the same time the necessity of producing a very accurate separation of coal or other material from refuse remains of the utmost importance.

Experience has taught that those apparatuses and proceaes which produce a satisfactorily ac- .curate and close separation invariably require small capacity apparatuses, and so if large 'volumes of material are to be treated, the installation cost, the space required, the power required, and the labor cost, becomes very high. 0n the other hand, if devices having large capacities are used, then inaccurate separation results and either an inadequately cleaned material is obtained or else a disproportionately large amount of recoverable and useful material is discharged with the waste.

We propose, therefore, to treat coal and similar materials on an apparatus embodying a method of treatment which will give very large capacity, and we will make the separation between coal and waste so high that there will be nothing but pure, clean coal discharged as the finished product.

The result of this is that a tremendously large proportion of coal passes out with the waste. We propose then to treat the waste, which in this case will be very rich in coal, though in volume'it will amount to a comparatively small proportion of the total, by a separate process on a separate apparatus of a totally different character which will make a close separation.

It will be understood that the material to be treated will come to the apparatus under ordinary circumstances with a minimum of size classification and will continue through the two stages of the process in a generally unsized condition. If desired, however, we will, after the refuse has been treated in the final treatment stage, classify as to size some of that refuse, crush it down'to a smaller size and retreat it in the same final treatment stage. Thus, while there will be under 'these circumstances a minimum of recirculation in the final stage, that recirculation will only apply to relatively large particles which will be crushed before recirculation. As a result of this, no particle will ever be recirculated more than once and only the larger particles will receive recirculation at all.

This is of the utmost importance in view of the fact that when an eflort is made to compensate for the. inaccurate separation of large capacity plants by frequent and continuous recirculation,

. a thoroughly unsatisfactory product ensues, both because of degradation giving an inordinately large 'a'moimt of sludge and because of the fact It is ap-' that the large pieces, having been recirculated, even if not completely broken up, have the edges rounded oil and made much less merchantable.

We propose in general then to submit coal and .similar material first to a high capacity rough separation by means of a liquid stream wherein the separating liquid and the material being treated travel together in the same general direc-' tion at high velocity, stratification taking place in a trough washer. The upper strata, containing pure coal, will be discharged as a finished product. The lower strata, containing refuse and a large amount of coal, will then be subjected to a separate treatment in a zone and in an apparatus where liquid is used, but where the liquid impinges upon the stream of material to be treated in such a way that the liquid and the material travel generally at right angles one to another. From this zone may be withdrawn three products. One, a pure refuse product which is discharged without further treatment. Another, a pure coal product which is discharged without further treatmentfiand a third a middings product which will then be screened, the smaller particles being discharged as' refuse, the larger particles being crushed and reduced in size, which crushed material will then be recirculated through the second treatment zone only and will thereafter be discharged as refuse and coal without the possibility of further recirculation.

Our invention is illustrated more or less diagrammatically in the accompanying drawings,

wherein: r

Figure 1 is a side elevation in part section of an apparatus adapted to carry out our process;

Figure 2 is a plan view; and

Figure 3 is a section along Figure 2.

Like parts are designated by like symbols throughout the specification and drawings.

I is a trough conveyor conveying the coal, or other material to be treated, to and discharging it into the hopper 2 whence it flows through the chute 3 across the apron 4 in the trough 5. 6 is a water pipe controlled by the valve I discharging water through the nozzle 8 into the trough beneath the apron 4 so that as the stream of coal passes down over the apron it meets a stream-of water coming from beneath the apron and the coal and water travel together in the same general direction down the chute 5. The chute 5 is supported for angular adjustment at 9. I0 is a trough washer, of any suitable type, it may, if desired, have a longitudinal dividing wall or dam l3 along its floor, which wall may also be found, if desired, in the chute 5. Its sole purpose is to constrain the stream of coal and water to generally parallel lines and discourage zigzag or cross flow in the trough.

In the floor of the trough the line 3-3 of across the trough are two refuse discharge ports l4, l5. There might be one or there might be more than two, depending upon the capacity desired, the characteristic of the coal and the like. Each of these ports is associated with suitable control and delivery elements.

i6 is a barrage at the upstream edge of the port.

i8 is a floor extending downwardly and rearwardly inclined from the upstream edge of the port. It terminates in a cylindrical portion I! and a rearwardly extended portion 2|] communicating with the elevator hopper 2|.

Extending upwardly from one side of the elevator hopper 2| is an elevator boot 29 containing a bucket elevator 30, which bucket elevator extends above the trough l0 and discharges into a chute 3|, which in turn discharges into a trough 32. If there is more than one port i5 and more than one elevator, each elevator similarly discharges, as indicated in Figure 1, into the trough 32. 33 is a chute in continuation of the trough Ill through which the cleaned coal from the upper strata of the trough is discharged as a finished product.

The elevator hoppers 2| and boots 29 are water tight and they are kept supplied with water from the trough I 0. Under ordinary circumstances, no make-up water is required, but if it should happen that the elevators carrying refuse and some water out of the trough carried enough to cause a downward current of water through the ports I and i5, then make-up water to prevent this may be added from a pipe 34 controlled by a valve 35 discharging into each hopper 29 adjacent its lower end, because it is sometimes desirable that the water below the wash trough In be static without any upward or downward current. I

As the refuse and coal travel down the trough 5 in the same general direction at high velocity, stratification will take place, the heavier particles seeking the bottom of the trough, the lighter particles stratifying themselves above' the heavier. In this particular instance, the coal at the top and the refuse at the bottom. If we were treating iron ore it would be the other way, and the refuse would be at the top and the iron ore at the bottom. In any event, the heavy material seeks the bottom and dams up behind the barrage ii to some extent. The height of this barrage is determined empirically depending upon the conditions of operation, and tends-to deflect the water stream and the coal and refuse particles in it upwardly away from the floor of.

the trough. The lighter particles will be more responsive to this deflecting action than the heavier, and so the downstream barrage i! will be adjusted, to catch the under strata and deflect the refuse into the port I, allowing the coal to pass over. If one port only is used, the barrage I! will be set so high that all the refuse particles will be intercepted and only coal will pass over. On the other hand, if there are more than one port, as shown in Figure 4, there are two, the upstream barrage I! will be set in such position that some refuse and coal will pass over it. The refuse will further bank up behind the down stream barrage l6 and the second barrage I! will be set high enough so that only coal will pass over and refuse will pass through the port l5, and the same thing will continue if more than two ports are used.

Once the refuse has been caught by the barrage l1, it must be removed, and it must be removed at a rate substantially as rapid as the rate at which the barrage catches it because otherwise if it is removed too fast too much coal will come out and if it is removed too slow, the refuse will pile up and be washed over the barrage l1.

Mounted for convenience on cross frames 36 associated with the cover I! of the trough washer III, is a reduction gear motor 31 which drives a variable speed control gear 38 which'in turn through belt 39, gear 40, pinion ll, belt 42 and gear 3 drives the star wheel gate 24. The operator, by manipulating the variable speed control gear 33, may control the rate of speed at which the star wheel operates and so control the rate at which refuse is discharged through the gate I4 because the star wheel 24 offers when at rest a positive obstruction to flow through the port H. The elevators 30 in the boots 2!! are driven by motors H, belts 45 and pulleys l6, and it is necessary that these elevators be driven only at such a. speed as will be sufficient to take the maximum amount fed to the hopper 2| by the star wheel 24.

The chute 32 conducts the refuse discharged from the elevators 30 to a jig washer 45. There will ordinarily be enough water elevated with the refuse by the conveyors 30 to insure the flow of the refuse along the chute 32 to the jig. If necessary, however, an additional water supply may be provided from pipe I48 controlled by valve 41. The refuse is discharged from the chute 32 into the water bed of the jig and travels in the direction of the arrows in Figure 2 across the air cells 48, 49. These air cells are closed at their upper extremeties by perforated or screen floors 50, 5|. An adjustable barrage 52 is interposed between the floors 50 and 5|. The. floor 50 slopes downwardly in a direction opposed tothe flow of the refuse. The floor 5| is generally horizontal. The solid material is Stratified on these floors with the refuse seeking the lower strata and the coal the upper. The general direction of travel is from the right to the left in Figure 1 and the coal and some of the refuse travels over the barrage 52, the final separation taking place on the floor 5|. The refuse caught by the barrage 52 on the floor 50 passes out through the port 53 controlled by a star wheel gate 54, discharges into the elevator boot 55 where the elevator 56 carries it up above the water level, discharging it into a hopper 51 whence it runs offas finished refuse through a chute 58, no further treatment for this refuse being contemplated. The coal of the upper strata is discharged from the floor 5| through a coal chute 59 and may be mixed with the coal discharge through the chute 33 if desired. The refuse, sinking to the bottom along the floor 5|, together with a certain amount of bone coal, passes out through the port 6' controlled by a similar star wheel gate 6|, is discharged into the elevator boot 6!, raised by the elevator 53, is discharged into a hopper 64, travels over ascreen 65, the fines being discharged as refuse without further treatment. The material which falls to pass through the screen 55 passes through a crusher 55, travels along a chute 61, back to the chute 32, and is recirculated. Thus only that refuse larger than a predetermined minimum is recirculated and it is crushed before recirculation down to such a size that upon its next passage through the machine it will pass through the screen and escape.

The pulsation of the water column in the cells water ceases.

i In the specification and in 48 and 49 iscaused by automatic control valves 68 which are supplied with air from an air chamber 69. Manual control valves III are interposed between the pulsating valve 68 and the air chamber. It will. be understood that each of these valves 68 admits air into a chamber H on one side of the jig. Air is alternately admitted and released from those chambers. When it is admitted under pressure it forces the water up. When it is released the upward movement of the The result of this is that there is a pulsating effect of .the water applied directly to the sheet of coal traveling over the screened or perforated fioors at the under side/of the coal bed. This pulsating effect of the water only forces separating and floating streams of water upwardly throughthe bed and insures stratification, and thus the coal in its passage through the apparatus is first subjected to a separating effect in the trough washer yvherein water and coal travel in generally the same direction, and then is subjected to a separating effect wherein the water and coal travel generally at right angles, the first treatment being a large capacity generally inaccurate treatment and the second treatment being a small capacity highly accurate separation.

the claims we have I referred to coal and refuse merely for the sake .of convenience and because it happens that this process and apparatus has been successfully used on coal. It will be understood of course, however, that the process and apparatus is equally applicable'to the treatment of any kind -of material which can be gravitally separated, and sometimesthe lighter material is the value and the heavy material refuse, as in the'case of coal, and at values will be changed in design to take care of proportional diflerences in volume and weight,-

and the illustration bymeans of a coal handling apparatus and the use of language especially pertinent to coal treating is merely for the sake of convenience and it is understood that that language is not intended to specifically limit the claims to a coal treating apparatus. I I

It will be understood, also, that the crushing and recirculating step may be omitted. Under some circumstances it is desirable, in other cases it is not necessary.

By the term "pure refuse and pure coa as used in the specification and claims, we do not of course mean to refer to chemically pure refuse and coal. We are using the term in the way in which it is used in the art. Clean coal or pure coal means coal which is sufficiently free of ash to be commercially satisfactory for the conditions under which it is used. Pure refuse or clean refuse means refuse wherein the amount of coal passing out is reduced to 'a satisfactory minimum.

. zone, there subjecting it to the stratification eifect of liquid flowing in the same general direction as the solids, discharging the lighter solids alone from the upper strata in the separation zone, and withdrawing the heavier solids mixed with fighter solids from the lower strata thereof, conveying the mixed heavy and light solids to and through a secondary downwardly inclined treatment zone, and there subjecting them to the stratification effect of liquid pulsating in a direction generally at right angles to the direction of travel of the solids through the secondary zone, discharging the lighter solids alone from the upper strata. and withdrawin the heavier solids mixed with lighter solids from the lower strata, screening the mixed heavy and light solids and discharging the undersize from 1 the system, crushing the oversize solids and recirculating them through the secondary treatment zone.

'2. The method of gravltally separating comminuted solids which consists in discharging a continuous stream of the material to be separated into and through a primary treatment zone, there subjecting it to the stratification effect of liquid flowing in the same general direction as the solids, discharging the lighter solids alone from the upper strata in the separation zone, and withdrawing the heavier solids mixed with lighter solids from the lower strata thereof, conveying the mixed heavy and light solids to and through a secondary downwardly 3. The method of gravitally separating com-' minuted solids which consists in discharging a continuous stream of the material to be separated into and through a primary treatment zone, there subjecting it to the Stratification effect of liquid flowing in the same general direction as the-solids, discharging thelighter solids alone from the upper strata in the separation zone, and withdrawing the heavier solids mixed with lighter solids from the lower strata thereof, conveying the mixed heavy and light I solids to and through a secondary downwardly inclined treatment zone, and there subjecting them to the stratification. effect of liquid pulsating in a direction generally at right angles to the direction of travel of the solids t ugh the secondary zone, discharging the lighter sol-- ids alone from the upper strata. withdrawing the heavier, solids alone from the lower strata in-the upstream portion of the secondary treat-. ment zone, withdrawingthe heavier solids mixed.

with lighter solids from the lower strata of the downstream portion of the secondary treatment zone, screening the mixed heavy and light solids and discharging the undersize from the system, crushing the. oversize solids and recirculating them through the secondary treatment zone.

NELSON L.'DAVIS. JAMES D. S. DRINKWATER. THOMAS O. CARLISII. 

